I've heard of a few people asking how to do this so thought i'd make this little Blue Peter stylie write up on how i did it, whilst this may or may not be the best way to do it, it worked for me. Not many pictures of the build itself because I was more interested in getting the job done but you should get the jist of it.

If theres anything you feel i could explain in more detail just leave a comment but i hope this helps.

in this next one you can see where the bolts have gone.
-3x silver nuts and bolts attatch the mounting plate to the "L" shaped mounting brackets which were welded to square sections already part of the sunroof (to raise the sunroof up and down so that it looks more natural from the outside washers were used between the mounting plate and the roof)
-2x black bolts are part of the original sunroof setup and attatch the mounting plates to original screw holes in roof

2 pics from the outside, sealing not done too well and needs tidying but it stops you from getting soggy Corbeaus which i learnt the hard way, 'doh! We used black fishtank sealent but i'm sure theres plenty of other products you can use.

As said any questions just ask.
Hope it helps

I would rather lose by a mile because i built my own car, than win by an inch because someone else built it for me.